1. Field of the Invention
The present invention relates to an access limitation method for use in an information recording/reproducing device that can effectively limit an access.
2. Description of the Related Art
Recently, information processing devices have been improved, and it has become essential to hold and use information as electronic data that can be read by information processing devices on the business scene, etc. In such a case, electronic data can be copied with ease. Therefore, it is necessary to prevent an important document, etc. from being easily copied, and to guarantee that the document is an original. Normally, such an important document is held by being encrypted, and only a person who knows a particular key can decrypt the document. However, if an important document is only encrypted with a key, anybody can view the document in the case where the key is leaked out due to some reason or other. Accordingly, to further secure confidentiality, an access to electronic data is limited by using information specific to a device that is used to read a medium storing the electronic data.
Namely, an encrypted code itself generated from an encryption circuit can be leveraged as an access limitation if a key does not match. Additionally, a medium, to which device-specific information is written, enables a device to make an access only if the device matches the written device-specific information. Key information is registered to an encryption device, which has a mechanism for authorizing the use of a key according to a user ID/password. Accordingly, if a device such as a PC, an information recording/reproducing device, etc. is lost or damaged, a device having exactly the same device-specific information is required. However, there are no alternative methods.
Conventionally, if a device being a medium reading device such as a PC, an information recording/reproducing device, etc. becomes unavailable due to a fault, etc., specific information registered to the device is lost, and there are no measures to restore the information. Since a function for reading device-specific information does not exist, device-specific information must be directly written to a corresponding device. If attempts are made to register specific information to a device at a remote site or many devices, this requires much labor.
Additionally, if an encryption device is stolen, and its key information is also stolen, data can be decrypted and viewed. It is possible to implement a configuration where device-specific information is written to a medium, which can be read only by a device having the written device-specific information. However, if only information specific to one device is written to a medium, and if the device is damaged, the medium can never be used.